bw@gnu.ai.mit.edu (nobody:*:-2:60001:I. N. Cognito:/:) (04/22/91)
I recently installed a Mitsubishi 40 mb 28 ms hard disk in my AT clone, as a second drive driven by an MFM controller. The disk intermittently seems to get "caught", i.e., times out when trying to read out the FAT #1 table, and causes an error. CHKDSK will indicate a bad FAT #1 table, bad sector in FAT table, one moment, but the next time I try CHKDSK a few secs later, everything will be normal. When the problem first started, I ran both Norton and Mace disk utilities to look for bad sectors, and it never came up with any problems. I backed up the FAT table with the Mace backup, and this solved the problem for about a day (but since the problem is intermittent, perhaps it simply didn't recur during this time). The disk was purchased from Hard Disks International in Phoenix. They said perhaps there was a marginal sector, and that I should run a disk utility to check the disk, but I have repeatedly and no problems are revealed except a bad sector in FAT table occasionally. Running a speed-disk compression program or a FAT backup really doesn't solve the problem. Do I have a bad disk, a bad controller (never has there been a problem on my cheap Miniscribe disk over the past 5 years, run on the same computer), or incompatibility in the controller/disk settings? Bruce Waldman bw@harvarda.harvard.edu bw@gnu.ai.mit.edu .....!uunet!harvard!husc4!waldman2
jcburt@ipsun.larc.nasa.gov (John Burton) (04/22/91)
In article <15150@life.ai.mit.edu> bw@gnu.ai.mit.edu (nobody:*:-2:60001:I. N. Cognito:/:) writes: >I recently installed a Mitsubishi 40 mb 28 ms hard disk in my >AT clone, as a second drive driven by an MFM controller. The >disk intermittently seems to get "caught", i.e., times out >when trying to read out the FAT #1 table, and causes an error. >CHKDSK will indicate a bad FAT #1 table, bad sector in FAT [...] >Hard Disks International in Phoenix. They said perhaps there was >a marginal sector, and that I should run a disk utility to check >the disk, but I have repeatedly and no problems are revealed except >a bad sector in FAT table occasionally. From your discription, I'll have to agree with the folks from HDI...sounds like you have a marginal sector that doesn't hold the information properly (drops a few bits here and there). Also, your FAT #1 table is recorded on that sector => flakey FAT... > Running a speed-disk >compression program or a FAT backup really doesn't solve the problem. Of course they don't solve the problem, they just rearrange/rerecord the information, they *don't* "fix" the media and they *don't* move the FAT away from the flakey sector. What you need to do is move the FAT and mark the sector as bad. This can be somewhat difficult & time consuming because the sector is not bad (bad all the time) is just flakey. One possibility is using something like Norton's Disk Doctor, which will mark the sector as bad and move the FAT. Unfortunately with a flakey sector you might have to run it repeatedly until it does find the sector being bad. Another alternative is to backup your disk and do a low level format... If you purchase the disk from HDI and it has >32 MB (Mitsubishi MK535 ?) you probably got a copy of ONTRAC's Disk Manager and Disk Technician (diagnostics). What you want to do is this: 1) Get a cup of coffee/tea/soda (this might take awhile) 2) Backup your hard disk 3) Run DiskManger in the manual mode (DM /M I believe) 4) Make sure you have the Drive Parameters configured properly 5) Run the surface scan (verify surface) option. 6) you *might* have to run this several times, since the sector is flakey and not totally bad. 7) what you're looking for is a bad sector/cylinder near the begining of the disk (assuming you don't divide the drive into multiple logical drives, or your problem is with the first logical drive). I'm not sure exactly which cylinder it would be, but it would probably be somewhere between cylinder 0 and cylinder 10 (I don't have a manual with me, and my memory is a bit flakey at times...:-) 8) once you have located the flakey sector, do a low level format of the disk and MAKE SURE that the cylinder containing the flakey sector is marked bad (you can tell the format program which cylinders you want marked as bad... do it!) 9) Now partition the disk (I prefer to use MS-DOS's FDISK instead of Disk Manager for this purpose), and do a high-level format and restore your files... >Do I have a bad disk, a bad controller (never has there been a >problem on my cheap Miniscribe disk over the past 5 years, run >on the same computer), or incompatibility in the controller/disk >settings? > Nope, you don't have any of these things...just a flakey sector that happens to be the residence of FAT #1...just like HDI said...:-) >Bruce Waldman >bw@harvarda.harvard.edu >bw@gnu.ai.mit.edu >.....!uunet!harvard!husc4!waldman2 good luck...if you have any questions feel free to email... John +--------------------------------------------------------------------+ | John Burton | | G & A Technical Software | | jcburt@gatsibm.larc.nasa.gov | | jcburt@cs.wm.edu | | | | Disclaimer: Hey, what can I say...These are *my* views, not those | | of anyone else, be they employer, school, or government| +--------------------------------------------------------------------+
mvolo@uncecs.edu (Michael R. Volow) (04/23/91)
If your having trouble with the system area of a new Mitsubishi MR535, ask for a replacement. Problems in this area of the disk can get worse. The Mitsubishi is normally an excellent HD often formatting with *no* bad sectors. Yours may be lemon. Even if the disk can be "fixed" with a utility such as Spinrite, you're better off with a new disk. -- Michael Volow, Psychiatry, Durham VA Med Center, Durham NC 27712 919 286 0411 Ext 6933 mvolo@ecsvax.edu